url: improve URLSearchParams creation performance

PR-URL: #47190
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>

Author: anonrig

lib/internal/url.js

@@ -2,6 +2,7 @@
 
 const{
  Array,
+ ArrayIsArray,
  ArrayPrototypeJoin,
  ArrayPrototypeMap,
  ArrayPrototypePush,
@@ -157,52 +158,74 @@ function isURLSearchParams(self) {
 }
 
 classURLSearchParams{
+[searchParams]=[];
+
+// "associated url object"
+[context]=null;
+
 // URL Standard says the default value is '', but as undefined and '' have
 // the same result, undefined is used to prevent unnecessary parsing.
 // Default parameter is necessary to keep URLSearchParams.length === 0 in
 // accordance with Web IDL spec.
 constructor(init=undefined){
-if(init===null||init===undefined){
-this[searchParams]=[];
+if(init==null){
+// Do nothing
 }elseif(typeofinit==='object'||typeofinit==='function'){
 constmethod=init[SymbolIterator];
 if(method===this[SymbolIterator]){
 // While the spec does not have this branch, we can use it as a
 // shortcut to avoid having to go through the costly generic iterator.
 constchildParams=init[searchParams];
 this[searchParams]=childParams.slice();
-}elseif(method!==null&&method!==undefined){
+}elseif(method!=null){
+// Sequence<sequence<USVString>>
 if(typeofmethod!=='function'){
 thrownewERR_ARG_NOT_ITERABLE('Query pairs');
 }
 
-// Sequence<sequence<USVString>>
-// Note: per spec we have to first exhaust the lists then process them
-constpairs=[];
+// The following implementationd differs from the URL specification:
+// Sequences must first be converted from ECMAScript objects before
+// and operations are done on them, and the operation of converting
+// the sequences would first exhaust the iterators. If the iterator
+// returns something invalid in the middle, whether it would be called
+// after that would be an observable change to the users.
+// Exhausting the iterator and later converting them to USVString comes
+// with a significant cost (~40-80%). In order optimize URLSearchParams
+// creation duration, Node.js merges the iteration and converting
+// iterations into a single iteration.
 for(constpairofinit){
-if((typeofpair!=='object'&&typeofpair!=='function')||
-pair===null||
-typeofpair[SymbolIterator]!=='function'){
+if(pair==null){
 thrownewERR_INVALID_TUPLE('Each query pair','[name, value]');
-}
-constconvertedPair=[];
-for(constelementofpair)
-ArrayPrototypePush(convertedPair,toUSVString(element));
-ArrayPrototypePush(pairs,convertedPair);
-}
+}elseif(ArrayIsArray(pair)){
+// If innerSequence's size is not 2, then throw a TypeError.
+if(pair.length!==2){
+thrownewERR_INVALID_TUPLE('Each query pair','[name, value]');
+}
+// Append (innerSequence[0], innerSequence[1]) to querys list.
+ArrayPrototypePush(this[searchParams],toUSVString(pair[0]),toUSVString(pair[1]));
+}else{
+if(((typeofpair!=='object'&&typeofpair!=='function')||
+typeofpair[SymbolIterator]!=='function')){
+thrownewERR_INVALID_TUPLE('Each query pair','[name, value]');
+}
 
-this[searchParams]=[];
-for(constpairofpairs){
-if(pair.length!==2){
-thrownewERR_INVALID_TUPLE('Each query pair','[name, value]');
+letlength=0;
+
+for(constelementofpair){
+length++;
+ArrayPrototypePush(this[searchParams],toUSVString(element));
+}
+
+// If innerSequence's size is not 2, then throw a TypeError.
+if(length!==2){
+thrownewERR_INVALID_TUPLE('Each query pair','[name, value]');
+}
 }
-ArrayPrototypePush(this[searchParams],pair[0],pair[1]);
 }
 }else{
 // Record<USVString, USVString>
 // Need to use reflection APIs for full spec compliance.
 constvisited={};
-this[searchParams]=[];
 constkeys=ReflectOwnKeys(init);
 for(leti=0;i<keys.length;i++){
 constkey=keys[i];
@@ -224,13 +247,10 @@ class URLSearchParams {
 }
 }
 }else{
-// USVString
+// https://url.spec.whatwg.org/#dom-urlsearchparams-urlsearchparams
 init=toUSVString(init);
 initSearchParams(this,init);
 }
-
-// "associated url object"
-this[context]=null;
 }
 
 [inspect.custom](recurseTimes,ctx){

test/parallel/test-whatwg-url-custom-searchparams-constructor.js

@@ -47,6 +47,10 @@ function makeIterableFunc(array) {
 assert.throws(()=>newURLSearchParams([null]),tupleError);
 assert.throws(()=>newURLSearchParams([{[Symbol.iterator]: 42}]),
 tupleError);
+
+assert.throws(()=>newURLSearchParams(
+makeIterableFunc([['key','val','val2']])
+),tupleError);
 }
 
 {